Field of the Invention
Embodiments of the present disclosure relates to the field of liquid crystal panel manufacturing technology, and in particular to a liquid crystal drop filling system for manufacturing a liquid crystal panel and a related control methods.
Description of the Related Art
An existing TFT-LCD substrate mainly comprises a color film (CF) substrate and a thin film transistor (TFT) substrate. These two substrates have their surrounding sealed by a sealant at a bonding process section, at same time the sealant seals the liquid crystal in a box so as to, form a liquid crystal panel. At present, a commonly used liquid crystal injection process is a process so called One Drop Filling (abbreviated as ODF). In general, the reference value of the liquid crystal drop rate may be calculated theoretically. After considering key parameters such as the thickness of the film, the height of the photo spacer (PS) on side of the color film, the box thickness after assembly, a plurality of different liquid crystal amounts (LC Split) within a range around the calculated reference value by ±6% were prepared, and the final center liquid crystal amount and the variable range of the liquid crystal amount (influenced by normal fluctuation of the processes) were determined by a LC Margin evaluation experiment.
For example, FIG. 1 illustrates an exemplary flow chart of a control method for a liquid crystal drop filling/instillation system according to the prior art. As shown in the drawing, after a start, a liquid crystal panel is obtained by the liquid crystal drop filling process (step 101), and then the obtained liquid crystal panel is subject to a visual inspection (usually in a dark room) (step 102), determining by the inspection whether the sealant is broken, whether the liquid crystal is not filled, whether there is a defect which may be visually inspected, such as a bad/poor appearance (step 103). After it is determined that the liquid crystal panel is qualified, the inspection procedure is finished, and then the liquid crystal panel is sent to the following relevant procedures. If it is determined that the liquid crystal panel is defective, it will determined according to the severity of the defect how to dispose of the liquid crystal panel, for example, recycling or discarding, etc., and then, the inspection process is finished. After it is determined that the liquid crystal panel is defective due to the process (e.g., liquid crystal drop rate, liquid crystal drop accuracy, liquid crystal pattern, etc.), a complex LC Margin experiment as described above is performed to re-determine the relevant process parameters (step 104), then the parameters of ODF process are adjusted according to the parameters determined by the experiment so as to improve product quality.
The above-mentioned way of determining the amount of center liquid crystal has many drawbacks: 1) the reference value is calculated, and it may not be taken into account the box thickness difference due to the processing fluctuations (for example, the difference in uniformity of film thickness, difference in volume of Fan-out region, etc.); 2) in the production processes, there is no effective mechanism for monitoring the amount of liquid crystal drop, it may be determined whether the amount of liquid crystal is appropriate only after the LC margin test, which brings about problems such as an excessive long evaluation cycle and an excessive number of LC Split, and so on.
Further, the present liquid crystal drop filling process lacks an inspection mechanism for peripheral defects such as peripheral yellowing, light leakage, and may not performing a pre-checking before the product is finished, thus easily resulting in a waste of materials and money.